Reducing mind wandering using continuous theta burst stimulation

Mind wandering (MW) involves an attentional drift away from an external task to internal thoughts and goals. In the last decade, a substantial number of studies have investigated the possibility of influencing MW using transcranial direct current stimulation (tDCS). However, the accumulated evidence suggests that tDCS may not be sufficiently strong to reliably affect MW propensity. Therefore, we applied repetitive transcranial magnetic stimulation (rTMS) with an inhibitory continuous theta-burst stimulation (cTBS) protocol targeting the left angular gyrus (AG) to interfere with MW propensity in healthy adults. Since the AG is a core region of the default-mode network (DMN), which is believed to play a major role in the initiation and maintenance of MW episodes, we hypothesized that cTBS would reduce MW during a demanding cognitive task. In a triple-blind, crossover design, participants performed four blocks of the finger-tapping random-sequence generation task (FT-RSGT) with three interleaved bouts of real or sham cTBS. We found that real cTBS reduced both self-reported MW propensity and behavioural variability, an objective marker of MW, while maintaining comparable levels of executive task performance. These results indicate that cTBS targeting the DMN may be an effective protocol to reduce MW, which may have important implications for basic and applied research.